Composite panel

Abstract

A continuous process for making a core for a composite panel comprising cutting spaced apart tongues in columns from a metallic sheet, the tongues being foldable about base lines in the columns each base line being separated from the next tongue in the column by a web; folding the sheet to form a castellated structure having continuous side walls constituted by the spaces between adjacent columns of tongues with the webs of adjoining rows respectively lying in spaced apart parallel planes and oppositely folding the tongues of adjoining columns to lie alongside adjacent side walls with their extremities remote from their base lines extending in an appropriate one of the planes. The invention also includes a composite panel comprising the core covered on each side with sheet material as well as a process for making such a panel.

I claim: 
     
       1. A continuous process for making a core for a composite panel comprising cutting spaced apart tongues in columns from a metallic sheet characterised in that the tongues are foldable about base lines in the columns each base line being separated from the next tongue in the column by a web; folding the sheet to form a castellated structure having continuous side walls constituted by the spaces between adjacent columns of tongues with the webs of adjoining rows respectively lying in spaced apart parallel planes and oppositely folding the tongues of adjoining columns to lie alongside adjacent side walls with their extremities remote from their base lines extending in an appropriate one of the planes. 
     
     
       2. A process according to claim 1 in which facing sheets are secured to the formed core in the same continuous process to form a composite panel. 
     
     
       3. A process according to claim 1 in which metal sheet from a first coil is passed intermittently successively through a slitting mechanism for forming the tongues in the plane of the sheet; a castellation former and a tag bender. 
     
     
       4. A process for making a composite panel in which a core formed according to claim 1 is passed continuously through profile compression means which closes the side walls tightly against the tongues and in which after said means, sheet material from second and third coils is passed respectively on each side of the core and stuck thereto. 
     
     
       5. A process according to claim 4 in which the core and said sheet material is passed through a heated chamber containing pinch rolls for the panel which, in conjunction with the profile compression means, maintains the core with its side walls closed tightly against the tongues. 
     
     
       6. A process according to claim 5 in which each sheet material has its outer surface pre-painted and the inner surface is coated with an adhesive before passing through the chamber and the temperature of the latter is sufficiently high to cause the adhesive to set but sufficiently low that the pre-painted surfaces are not damaged. 
     
     
       7. A process according to claim 6 in which the temperature is between 50° C. and 80° C. 
     
     
       8. A process according to claim 7 in which the adhesive has a polyurethane base. 
     
     
       9. A composite panel comprising a core having spaced apart tongues arranged in columns in a metallic sheet characterised in that the tongues are folded about base lines in the columns each base line being separated from the next tongue in the column by a web; the sheet being castellated having continuous side walls constituted by the spaces between adjacent columns of tongues with the webs of adjoining rows respectively lying in spaced apart parallel planes and the tongues of adjoining columns lying alongside adjacent side walls with their extremities remote from their base lines extending in an appropriate one of the planes and the core being covered on each side with sheet material stuck thereto. 
     
     
       10. A composite panel according to claim 9 in which sheets are metallic and their outer surfaces are pre-painted. 
     
     
       11. A composite panel according to claim 9 in which the core and the outer sheets are of aluminium alloy.